In recent times, image scanners, video capture cards and digital still and video cameras have made it easier for people to capture photographs, video sequences and other images. These images are often stored on personal computers and other computer related devices. Due to the large number of images that are often stored on these devices, there is a need for users of such devices to be able to access the stored images for viewing, sharing and organisation. Software applications (e.g., image browser software applications) and dedicated devices have been developed to aid users in the tasks of viewing, sharing and organising collections of images.
When viewing a collection of captured and stored images on a computer screen or the like, using an image browser software application, for example, the images are typically displayed as a two dimensional (2D) grid of small images known as a ‘thumbnail grid’. For example, FIG. 1 shows an application window 100 of a user interface comprising a thumbnail grid 105. The thumbnail grid 105 comprises a plurality of images including images 102, 103 and 104. The remaining non-referenced rectangles shown in phantom lines in FIG. 1 also represent images. However, the images represented by these remaining rectangles will not be referred to specifically. A reference to “the images 102, 103 and 104” below will be considered to generically refer to all of the images represented in FIG. 1 including the images shown in phantom lines, unless a reference is made to a specific image (e.g., the image 102).
The image 102 of FIG. 1 is a photograph in landscape orientation, the image 104 is a photograph in portrait orientation and the image 103 is a panoramic photograph.
The images 102, 103 and 104 of the application window 100 may alternatively be arranged as a ‘stack’ 205, as seen in FIG. 2. The application window 100 comprising the images 102, 103, 104 arranged as the stack 205 may also be used as part of the user interface of an image browser application, for example. As seen in FIG. 2, in the stack 205, the first image 102 is displayed in front of (or at the top of) the stack 205 with each subsequent image 103 and 104 being displayed behind (or below) a previous image. Each subsequent image 103 and 104 of the stack 205 is typically offset in one or more directions so that a portion of each image (e.g., 103) may be seen behind a previous image. For example, a portion 106 of the image 103 is seen behind the first image 102.
Navigation of the collection of images 102, 103 and 104 in the stack 205 may be performed by moving the viewpoint of a user forward or backwards with respect to the stack 205. Navigation of the images 102, 103 and 104 may also be performed by re-shuffling the order of the images 102, 103, 104 in the stack 205.
The ratio between the width and height of an image is commonly referred to as the ‘aspect ratio’ of the image. A common property of the images within a collection of images is that there is a range of different sizes and aspect ratios. This is especially the case when the images of the collection are oriented so that their content is suitable for viewing. For example, when taking photographs, it is common for a photographer to orient a camera in either ‘landscape’ (or ‘wide’) orientation for certain types of images or in ‘portrait’ (or ‘tall’) orientation for other types of images. Additionally, ‘panoramic’ (very wide) images may exist within a collection of images. Further, video images often have a different aspect ratio compared to still images. A user may also crop or resize images to any particular size or aspect ratio depending on the content of the images and the particular preferences of the user.
Having a collection of images with different sizes and aspect ratios can cause a problem for image browser software applications, for example, in which a collection of images is being displayed as a regular geometric layout, such as the thumbnail grid 105 of FIG. 1. In particular, larger sized images affect the layout of the images so that a regular geometric layout may no longer be possible and/or the same number of images may not be able to be displayed within the application window 100 as if the images were of the same size. This problem may be overcome by using a ‘bounding box’ of regular size and shape to display each image of the collection. In this instance, each image may be scaled to fit wholly within a corresponding bounding box whilst maintaining the aspect ratio of the image. For example, each of the images 102, 103 and 104 of the thumbnail grid 105 has a corresponding bounding box 102A, 103A and 104A. As seen in FIG. 1, each of the images 102, 103 and 104 has been scaled to fit wholly within the corresponding bounding box 102A, 103A and 104A, respectively.
However, a disadvantage of scaling the images 102, 103 and 104 to fit within the bounding boxes 102A, 103A and 104A is that the relative proportion of space used to display each image in the application window 100 must vary according to the aspect ratio of each image. A very wide ‘panoramic’ photographic image will fill only a small proportion of the bounding box corresponding to the image as the relative height of the image is small compared to the width of the image. For example, as described above, the image 102 is a photograph in landscape orientation, the image 104 is a photograph in portrait orientation and the image 103 is a panoramic photograph. As seen in FIG. 1, the image 103 fills a smaller proportion of the bounding box 103A compared with the images 102 and 104 and their corresponding bounding boxes 102A and 104A, respectively. In fact, the image 103 only fills a small portion of the bounding box 103A and any remaining space in the bounding box 103A is unused.
When bounding boxes such as the bounding boxes 102A, 103A and 104A are used in the stack 205 of FIG. 2, the problem of unused space in the bounding boxes 102A, 103A and 104A is compounded. This is because with the exception of the front-most bounding box 102A, only a portion of each bounding box 103A and 104A is visible. For some images, all of the visible portion of a corresponding bounding box may be empty of any actual content. As seen in FIG. 2, the stack 205 comprises the images 102, 103 and 104 with corresponding bounding boxes 102A, 103A and 104A, arranged in perspective. The front-most bounding box 102A is shown in full with each of the other bounding boxes 103A, 104A being partially obscured by the bounding box in front. For the bounding boxes 103A and 104A, the visible portion of the bounding boxes 103A and 104A contains a significant proportion of unused space. This is due to the mismatch between the aspect ratios of the bounding boxes 103A and 104A and the aspect ratios of the corresponding images 103 and 104 contained within the bounding boxes 103A and 104A, respectively.
Thus a need clearly exists for a more efficient method of displaying a plurality of images, particularly where the images have irregular sizes and aspect ratios.